Genetic diversity and disease control in rice

Crop heterogeneity is a possible solution to the vulnerability of monocultured crops to disease. Both theory and observation indicate that genetic heterogeneity provides greater disease suppression when used over large areas, though experimental data are lacking. Here we report a unique cooperation among farmers, researchers and extension personnel in Yunnan Province, China—genetically diversified rice crops were planted in all the rice fields in five townships in 1998 and ten townships in 1999. Control plots of monocultured crops allowed us to calculate the effect of diversity on the severity of rice blast, the major disease of rice. Disease-susceptible rice varieties planted in mixtures with resistant varieties had 89% greater yield and blast was 94% less severe than when they were grown in monoculture. The experiment was so successful that fungicidal sprays were no longer applied by the end of the two-year programme. Our results support the view that intraspecific crop diversification provides an ecological approach to disease control that can be highly effective over a large area and contribute to the sustainability of crop production.

[1]  A. Roelfs,et al.  The Cereal Rusts , 1908, Botanical Gazette.

[2]  K. Frey,et al.  Multiline Cultivars as a Means of Disease Control , 1969 .

[3]  P. Galton,et al.  THE POSTURE OF HADROSAURIAN DINOSAURS , 1970 .

[4]  James G. Horsfall,et al.  Plant Disease: An Advanced Treatise , 1978 .

[5]  S. Ou.  Pathogen Variability and Host Resistance in Rice Blast Disease , 1980 .

[6]  J. Jenkyn,et al.  Strategies for the control of cereal disease , 1981 .

[7]  S. Kiyosawa.  Genetics and Epidemiological Modeling of Breakdown of Plant Disease Resistance , 1982 .

[8]  M. Wolfe,et al.  The spread oi Erysiphe graminis f. sp. hordei in mixtures of barley varieties , 1984 .

[9]  M. Wolfe,et al.  Selection on Erysiphe graminis in pure and mixed stands of barley , 1984 .

[10]  M. Wolfe.  The Current Status and Prospects of Multiline Cultivars and Variety Mixtures for Disease Resistance , 1985 .

[11]  R. M. Alexander,et al.  Mechanics of posture and gait of some large dinosaurs , 1985 .

[12]  William E. Fry,et al.  Plant disease epidemiology , 1986 .

[13]  Charles Francis,et al.  Multiple Cropping Systems , 1986 .

[14]  Stephen M. Gatesy,et al.  Caudofemoral musculature and the evolution of theropod locomotion , 1990, Paleobiology.

[15]  S. Gatesy,et al.  Bipedal locomotion: effects of speed, size and limb posture in birds and humans , 1991 .

[16]  S. Gatesy.  Hind limb scaling in birds and other theropods: Implications for terrestrial locomotion , 1991, Journal of morphology.

[17]  G. S. Khush,et al.  Breeding Rice for Resistance to Pests , 1992 .

[18]  Z. Dong,et al.  A nearly complete skeleton of a new troodontid dinosaur from the Early Cretaceous of the Ordos Basin, Inner Mongolia, People's Republic of China , 1993 .

[19]  BJ Staskawicz,et al.  Molecular genetics of plant disease resistance , 1995, Science.

[20]  Paul Teng,et al.  Rice blast disease , 1996 .

[21]  Charles C. Mann,et al.  Reseeding the Green Revolution , 1997, Science.

[22]  W. Parton,et al.  Agricultural intensification and ecosystem properties. , 1997, Science.

[23]  David Tilman,et al.  The greening of the green revolution , 1998, Nature.

[24]  J. Elkinton,et al.  Spatial Scale and the Spread of a Fungal Pathogen of Gypsy Moth , 1998, The American Naturalist.

[25]  H. Leung,et al.  Rapid Population Analysis of Magnaporthe grisea by Using rep-PCR and Endogenous Repetitive DNA Sequences. , 1998, Phytopathology.

[26]  M. Norell,et al.  Two feathered dinosaurs from northeastern China , 1998, Nature.

[27]  M. Willig,et al.  The Relationship Between Productivity and Species Richness , 1999 .

[28]  Mark W. Schwartz,et al.  Choosing the Appropriate Scale of Reserves for Conservation , 1999 .

[29]  P. Sereno,et al.  The evolution of dinosaurs. , 1999, Science.

[30]  Farish A. Jenkins,et al.  Three-dimensional preservation of foot movements in Triassic theropod dinosaurs , 1999, Nature.

[31]  D. Henderson,et al.  Estimating the masses and centers of mass of extinct animals by 3-D mathematical slicing , 1999, Paleobiology.

[32]  K. Garrett,et al.  Epidemiology in mixed host populations. , 1999, Phytopathology.

[33]  X. Wang,et al.  A new species of Caudipteryx from the Yixian Formation of Liaoning northeast of China , 2000 .